字符串拼接

import (
    "fmt"
    "strings"
)

func StringJoin(args ...string) string {
    return strings.Join(args, "")
}

func StringBuilder(args ...string) string {
    var b strings.Builder
    // b.Grow(cap)
    for i := range args {
        b.WriteString(args[i])
    }
    return b.String()
}

func main() {
    s := fmt.Sprintf("%s %s“, "Hello", "world!")
}